A selective turn-off-on fluorescent probe for nicotine detection based on o-phthalaldehyde and glutathione derivative

Herein, a novel fluorometric approach is developed for the precise quantification of nicotine. This method utilized the derivatizing reaction between o-phthalaldehyde (OPA) and reduced glutathione (GSH), and derivatized product with tricyclic conjugated structure generate fluorescent emission. And the derivative exhibits a quantum yield of 33.46 % and distinct fluorescence "turn-off" quenching behavior in the presence of Cu²⁺ ions due to the GSH-Cu²⁺ complex formation. More importantly, when nicotine is introduced reaction system, the fluorescence restored ("turn-on") based on the nicotine-Cu²⁺ complex formation. Therefore, a fluorimetric sensor for nicotine detection is developed with lower detection limit (LOD) of 0.21 μg/mL. The developed method was successfully utilized to analyze nicotine content in electronic cigarette and cigarette bag samples, yielding satisfactory recovery rates ranging from 85.2 % to 111.8 %. The obtained results demonstrated comparable accuracy and confirmed the method's reliability and practical applicability.